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An easier, safer, and scalable approach to the synthesis of a trianionic pincer ligand and its use in the preparation of the Mo cyclic polymer catalyst [O2C((p-OMe-C6H4)C)Mo(η2-CHC t Bu)(THF)] (7) are reported. The synthesis of the [ t BuOCO]Me2 (1) ligand is simplified to a reaction that allows scaling up, thus reducing the main barrier to accessing cyclic polymer catalysts. The synthesis allows for the derivatization of the C ipso carbon of the central ring of the pincer. Taking advantage of this, a deuterium atom was substituted for kinetic isotope measurements. Complex 7 was tested for activity in the polymerization of phenylacetylene. Confirmation of the cyclic polymer topology comes from gel permeation chromatography (GPC), dynamic light scattering (DLS), and intrinsic viscosity (η) measurements.

The reactivity of phosphaalkynes, the isolobal and isoelectronic congeners to alkynes, with metal alkylidyne complexes is explored in this work. Treating the tungsten alkylidyne [ t BuOCO]W�C t Bu(THF) 2 (1) with phosphaalkyne (10) results in the formation of [O 2 C( t BuC=)W{η 2 -(P,C)À P�CÀ Ad}(THF)] (13-t Bu THF ) and [O 2 C(AdC=)W{η 2 -(P,C)À P�CÀ t Bu}(THF)] (13-Ad THF ); derived from the formal reductive migratory insertion of the alkylidyne moiety into a WÀ C arene bond. Analogous to alkyne metathesis, a stable phosphametallacyclobutadiene complex [ t BuOCO]W[k 2 -C( t Bu)PC-(Ad)] ( 14) forms upon loss of THF from the coordination sphere of either 13-t Bu THF or 13-Ad THF . Remarkably, the CÀ C bonds reversibly form/cleave with the addition or removal of THF from the coordination sphere of the formal tungsten(VI) metal center, permitting unprecedented control over the transformation of a tetraanionic pincer to a trianionic pincer and back. Computational analysis offers thermodynamic and electronic reasoning for the reversible equilibrium between 13-t Bu/Ad THF and 14.

Combining strain-promoted azide-alkyne cycloaddition (SPAAC) and inorganic click (iClick) reactivity provides access to metal 1,2,3-triazolates. Experimental and computational insights demonstrate that iClick reactivity of the tested metal azides (LM-N3, M...

Polymer waste is constantly growing, and the few existing solutions for recycling, reuse, and degradation are not viable long term. Carbon-carbon bond scission is a highly sought-after technology to assist...